Blackfin Tuna: water temperature and season

Fall through spring, first and last light. Anglrithm scores blackfin tuna at offshore spots on the Atlantic side and in the Keys. This page sets out what that score weighs and the cited studies behind it.

Water temperature

Evidence tier Well established

The tagged band for blackfin tuna is 71-80 °F. Ten blackfin tagged in the north-central Gulf of Mexico in April 2012 (nine full records) spent 89% of their time in 21.9-26.6 °C (71-80 °F) and 90% in the top 57 m. Fenton et al. 2015, Environmental Biology of Fishes 98:1141-1150 (evidence: moderate).

The band works in both directions. Fish feed along a dome, rising to an optimum and falling away past it, so water above the band counts against an hour just as water below it does. Outside the band, either way, no hour rates GOOD in the score, and an hour loses more the further out the water is.

Season

Best Nov to Apr, by the score's season weight.

The score's season weight by month, from the studies cited in the species profile; the outlined months are at 90% of its peak or better.

What the score weighs

  • SeasonWell establishedkeeps 100%
  • CurrentSmall real effectkeeps 50%
  • WindSmall real effectkeeps 50%
  • SeasSmall real effectkeeps 50%
  • Water tempWell establishedkeeps 100%
  • LightReal, but localkeeps 100%
  • SolunarPopular belief, not supportedkeeps 20%Labelled not supported: it stays visible, discounted, and is never promoted.
  • Wind vs currentSmall real effectkeeps 50%
Why each tier
  • Season: Season is the strongest single predictor in most recreational datasets, because it carries water temperature, migration and spawning together. Shaw et al. 2021, PLOS ONE 16:e0257882.
  • Current: No study we found ties a current speed or direction to catch for any fish in this app. Current decides whether you can hold a bait where you want it and how a drift sets up: off Southeast Florida the Gulf Stream runs fast close to the coast, and deep-drop boats stay under power to hold position. Treat a current pattern as a fact about your fishing more than about the fish. Davis, Cudney & Blankinship 2017, Bulletin of Marine Science 93:539-555. Lerner et al. 2013, Transactions of the American Fisheries Society 142:95-104.
  • Wind: Wind has a measurable effect on fish movement, apparently through dissolved oxygen, but it is small. The larger effect in any personal log is on you: wind decides where you can fish and whether you go at all, so a wind pattern in your own data is at least as likely to be about your choices as about the fish. Milardi et al. 2019, Aquatic Ecology 53:251-263. Shaw et al. 2021, PLOS ONE 16:e0257882.
  • Seas: Sea state mostly decides whether the trip happens and whether you can fish it well. Treat a sea-state pattern in your own log as a fact about your fishing, not about the fish. No direct angling-scale study found; labelled from mechanism.
  • Water temp: Fish are ectotherms, so appetite and digestion track water temperature along a dome: rising to an optimum, then falling away again. Warmer is not simply better. Snook energy demand roughly tripled from 15 to 25 C, and they were more likely to have empty stomachs when the water ran hot. Volkoff & Ronnestad 2020, Temperature 7:307-320. White et al. 2025, Marine and Coastal Fisheries 17:vtaf031, doi:10.1093/mcfafs/vtaf031.
  • Light: Dawn and dusk are well documented as movement and feeding windows for many inshore and coastal species, and the effect interacts with tide rather than standing alone. Viehman & Zydlewski 2017, PLOS ONE 12:e0176405.
  • Solunar: The best-powered test of solunar tables found nothing. One angler, 361 trips and 1,355 hours, seven commercial solunar services, corrected for multiple testing, with 99 percent power to detect a medium effect: no relationship between any solunar value and catch rate. Just two results were significant, and both were negative, with trips inside predicted minor windows yielding 42.5 percent fewer fish per hour. Air temperature beat every solunar prediction. Quigley, Gonzalez Murcia & Kauwe 2023, SN Applied Sciences 5:162.
  • Wind vs current: Wind blowing against the current stands the seas up: shorter, steeper and more likely to break than the same wind over slack water, which decides how a drift sets up and how long a day stays fishable. That is physics about the water, not evidence about the fish; no study we found ties it to catch. U.S. Coast Pilot 4, Chapter 3 (opposing wind and current on the Gulf Stream: sharply higher, steeper seas that can break; mechanism only). No catch study found.

Each factor's weight is multiplied by its evidence tier: well established and real but local keep all of it, a small real effect keeps half, and a popular belief that is not supported keeps a fifth. Guidance from the studies sits beside the score, never in it.

The studies

The whole evidence library

Entries read in full text or published by an agency. Entries read only in their abstract are listed on the science page with their numbers withheld.

Where it is scored

Today's score at any of them is free with an account; every fish has a page like this one.

Display only, not for navigation. Every figure here names its source; check the NWS marine forecast and the posted rules before you leave the dock.